Field of the Invention
The invention relates to a method for establishing a communication channel, preferably an embedded control channel, between a central network node and at least one network node to be integrated in a communication network.
Description of Related Art
Communication over a shared medium with techniques to manage access to the network to avoid collisions is well known in the literature (e.g. CSMA-CD method used in Ethernet). In the following, however, a different realization with a channel for shared downstream transmission and another channel for shared upstream transmission is assumed. Thus, it is not possible for the newly joining station to listen whether the shared medium is currently used.
There are also numerous ways of assigning network addresses to newly joining stations. These usually rely on a central network manager, which can assign addresses, for example IP addresses, from a database. This, however, requires that physical layer communication and Ethernet communication (using MAC addresses) are already working.
Regarding Ethernet connectivity there are also schemes to assign MAC addresses: usually, however, it is assumed that the likelihood that the MAC address is used elsewhere on the network is very low due to a much higher number of possible MAC addresses compared to the number of used devices (e.g. U.S. Pat. No. 7,961,724). This is true for LANs with a small number of attached devices and a large number of MAC addresses, which can be potentially used. This method, however, cannot be applied in cases in which a limited number of available addresses is available, only.
In connection with the realization of a wavelength-division multiplex passive optical network (WDM-PON), it is known to use an optical spectrum analyzer (OSA) to identify newly joining optical network units (ONUs) (e.g. EP 2 773 056 A1). This, however, requires additional costly components. Alternatively, this solution requires access to the receiver array, which is not possible in a standalone implementation.
In another realization, each ONU could be programmed on delivery with a unique media access control (MAC) address. This MAC address would also need to be programmed into the network management to make the central office or optical line terminal (OLT) aware of a newly joining ONU with a certain address. This additional programming requires additional effort.